Israel said one of its F-16 jets crashed in northern Israel on Feb. 10 after facing heavy anti-aircraft counter fire from Syria. (AP)

JERUSALEM — Israel carried out extensive airstrikes inside Syria on Saturday, targeting what the Israeli military said were air defense batteries and army bases as well as Iranian positions, in a day of dramatic cross-border confrontations as the threat of a wider regional conflict looms.

The Israeli military said it launched the “large scale attack” after one of its F-16 fighter jets crashed under Syrian antiaircraft fire. Eight Israeli jets had been responding to an incursion by an Iranian drone launched from Syrian territory by bombing a Syrian air base, Israel said.

Seeking to contain Iran and its proxies, Israel has regularly carried out airstrikes inside Syria, though not on this scale.

If a direct hit on the Israeli aircraft is confirmed, it would be the first time an Israeli jet has been brought down by enemy fire since 1982. The strikes that followed were Israel’s most significant bombardment inside Syria since the beginning of the nearly seven-year war — hitting 12 military sites in the country — eight Syrian and four that Israel said were Iranian.

Israeli Prime Minister Benjamin Netanyahu and Israeli military officials described the initial incursion as an Iranian “attack” and said it was Israel’s right and duty to respond. The Israeli army said the Iranian drone did not cross into Israel by accident and was on a “mission” but declined to give further details or comment on whether the drone was armed.

Israel has looked on with alarm as its archenemy Iran has extended its military reach and political influence in the region during conflicts in Iraq and Syria. Along with its Lebanese proxy Hezbollah, Iran has provided military support for Syrian President Bashar al-Assad during his country’s civil war, projecting an expanded presence close to Israel’s northern border.

Secretary of State Rex Tillerson, who will travel to the Middle East this week, reaffirmed in a phone call with Netanyahu on Saturday that “Israel has the right to defend itself,” said Undersecretary of State for Public Diplomacy and Public Affairs Steven I. Goldstein.

The United States, Goldstein said, is “deeply concerned” about the escalation of violence and holds Iran responsible.

But Iranian Foreign Ministry spokesman Bahran Qasemi disputed the Israeli account, describing the claim that an Iranian drone had crossed the border as “ridiculous.” He said the Syrian government had the right to defend itself by shooting down the Israeli jet.

The Syrian state news agency, meanwhile, described the airstrikes in Syrian territory as a “new Israeli aggression.” A military alliance backing Assad said that any other incursion by Israel would be met with “serious and fierce” retaliation.

The Israeli military released video it said shows an Iranian drone in Israeli airspace on Feb. 10, before it was destroyed by an Israeli attack helicopter. The alleged incursion was used as the pretext for Israeli strikes on what it described as Iranian targets in Syria. (Israel Defense Forces)

The Israeli strikes also riled Russia, which has forces deployed in Syria as part of Moscow’s effort to defend Assad’s government against a wide range of rebel groups seeking his ouster.

But Russia is seen by Israel as a key to de-escalating the heightening crisis by influencing Iran to contain its presence.

Moscow said the Israeli airstrikes on Syrian bases potentially imperiled Russian military advisers stationed there. “The creation of any threat to the lives and safety of Russian military servicemen currently in Syria on the invitation of its lawful government to help fight terrorists is absolutely unacceptable,” the Russian Foreign Ministry said in a statement.

Netanyahu said that he had spoken to Russian President Vladimir Putin to reiterate “our right and obligation to defend ourselves.” He said that the two leaders agreed that their military cooperation would continue.

Netanyahu’s statement came after the prime minister held an emergency meeting with Defense Minister Avigdor Lieberman at Israel’s military headquarters in Tel Aviv.

The surge in violence across the Israel-Syria border is the latest front in a multisided Syrian war that in recent days has seen heightened military operations in several places in the north and east of the country as well as close to the capital, Damascus. Russia, Iran, Turkey and the United States, as well as their local allies, are all engaged on the battlefield.

Israel and the United States have expressed serious concerns about the growing assertiveness of Iran and its ally Hezbollah.

“Iran’s calculated escalation of threat and its ambition to project its power and dominance places all the people of the region, from Yemen to Lebanon, at risk,” Goldstein said. “We will continue to push back on Iran’s malign activities, and we want an end to this behavior that threatens peace and stability.”

The Israelis have been particularly worried about what they say is a buildup of Hezbollah forces from the Syrian city of Palmyra to the country’s southwest corner bordering the Israeli-occupied Golan Heights. Aiming to assuage Israel’s concerns, the United States and Russia agreed last year to establish a cease-fire between Syrian government forces and rebel fighters near the southwestern Syrian town of Daraa. That agreement has mostly held.

But outside that small area, Hezbollah has continued to increase strength, Israel says. Israel has pointed to what it says are Hezbollah plants for assembling Iranian-supplied missiles that could be fired on Israel. And Israel has repeatedly carried out airstrikes against what it has described as Hezbollah convoys and operations.

“The Syrians are playing with fire that they are allowing the Iranians to attack Israel from their soil,” Lt. Col. Jonathan Conricus, a spokesman for the Israel Defense Forces, said Saturday. “The IDF is ready and capable to inflict a heavy price on anyone that attacks us.”

But the possible downing Saturday of the Israeli jet — and images of its burned remains — is a public relations boost for Assad. The Syrian government had been complaining that regular Israeli incursions were an affront to its sovereignty.

“Israelis must realize that they no longer have superiority in the skies nor on the ground,” Fares Shehabi, a member of the Syrian parliament representing Aleppo, said on Twitter. He said Syria had fired more than 24 surface-to-air missiles at Israeli jets. “Much more will be fired in the future . . . if Israel continues its aggressions.”

The Israeli military said it was investigating whether its jet was hit directly. Syria asserted that it was.

The conflagration began when an Iranian drone crossed into Israeli territory from Syria about 4:30 a.m. Saturday, according to the Israeli military. It was shot down by an Israeli attack helicopter.

The pro-Syrian military alliance, which includes Hezbollah and Iran, released a statement describing the Israeli claim that an Iranian drone had entered its airspace as a “lie and fabrication.”

But Conricus said that Israel was in possession of the remains of the drone and that Israeli officials were certain it was Iranian.

In response, Israel dispatched eight fighter jets to bomb the T4 military base near Palmyra, from where it says the drone was dispatched and controlled. Syria responded with “substantial . . . antiaircraft fire” and two Israeli pilots ejected from their F-16, which crashed inside Israel, according to the Israeli military. One of the pilots was severely injured, it said.

Civilians on both sides of the border were awakened by the military exchange.

“We can hear the sounds of the explosions,” said one Damascus resident, who spoke on the condition of anonymity. He said the sound of Syrian antiaircraft missiles was louder than usual.

Air raid sirens were triggered in residential areas on Israel’s northern border. Shlomo Mishal, 55, who lives in Beit Shean in northern Israel, said he awoke to the noises about 4:30 a.m.

“We heard a loud bang, but we did not know what was going on and ran downstairs to the shelter, a safe room in our home,” he said. Mishal said that his friends and neighbors in the town started sharing text messages and social media posts, with rumors flying about what had happened, until 8 a.m. when news stations gave details of the shooting down of an Iranian drone.

“The fact that this happened not far from our home, the fact there was an Iranian drone overhead is not nice and makes us uncomfortable,” Mishal said.

Eyal Ben-Reuven, a retired ­Israeli major general and member of parliament, said he hoped the strikes would spark a diplomatic push to protect Israel’s interests.

“The political leadership must say to the United States and Russia, ‘Take this event very, very seriously,’ ” he said. “ ‘You must stop the Iranians in Syria. You must. If you don’t do that, we will do that.’ ”

He said that as a member of the parliament’s foreign affairs and defense committee, he had met with Russian representatives three times in the past year and that Russia was well aware of Israel’s position. The United States lacks the leverage Russia has in Syria, he said.

After meeting with Putin, Netanyahu in a video statement said he told the Russian president that Israel viewed two developments with severe disapproval: “One, the attempts by Iran to base itself militarily in Syria and the second, Iran’s attempt to produce in Lebanon accurate weapons against the state of Israel. I made it clear to him that we will not agree to any of those developments and we will act accordingly.”

“I hope this will push the diplomatic efforts,” Ben-Reuven added. “This is serious. It’s not finished.”

Israeli military officials have acknowledged that the cost of any future war on the country’s northern border will be high. Israel fought a bloody 34-day war with Hezbollah in Lebanon in 2006. The conflict killed more than 1,000 people in Lebanon and 165 in Israel.

Since then, Hezbollah has built up its arsenal of rockets, which Israel estimates to be about 150,000 projectiles. Israel has expressed concern that Iran is transferring expertise and know-how to Hezbollah to boost the accuracy of those missiles.

Some Israeli military officials have said that a future war on the northern border could drag in both Lebanon and Syria.

Louisa Loveluck in Beirut, Karen DeYoung in Washington, Erin Cunningham in Istanbul and Anton Troianovski in Moscow contributed to this report.